Rock drill bit



W. A. HART ROCK DRILL BIT Sept. 22, 1964 Filed NOV. 7, 1961 INVENTOVR. Waller A. Hart United States Patent O 3,149,686 ROCK DRILL BIT Walter A. Hart, RR. 1, Box 225, Oroville, Wash. Filed Nov. 7, 1961, Ser. No. 150,769 3 Claims. (Cl. 175-417) This invention relates to bits and more particularly to that kind of a bit used for drilling through rock and the like.

One of the major reasons it usually takes so long to cut an opening through rock, usually solid, is the large number of work stoppages necessary for the repeated sharpening of the drill bits used in this type of work.

It is therefore one of the objects of this invention to provide a rock drill bit that has a much longer life than the drill bits now in every day use by reason of a more efficient design of the same.

Another object of this invention is to provide a rock drill bit that has the desired longer life by reason of the fact that its cutting edges are traveling in a most nearly longitudinal direction as will be hereinafter described.

Another object of this invention is to provide a rock drill bit that has a larger center area that chips away the rock without actually coming into the bit itself.

Another object of this invention is to provide a rock drill but that is all in one piece and therefore does not require any adjustments.

Still another object of this invention is to provide an improved rock drill bit that has all of the many desired advantages and none of the disadvantages of the present day bits of related design and construction.

Other and further objects and advantages of this rock drill bit will be hereinafter described, and the novel features thereof defined in the appended claims.

Referring to the drawing:

FIGURE 1 is a top view of my invention.

FIGURE 2 is a pictorial view of my invention.

FIGURE 3 is a side view of my invention taken in the direction indicated by the arrow and numeral 3 on FIG- URE 1.

Similar reference characters refer to similar parts throughout the several views of the drawing.

Having reference now to the drawing in detail, there is generally indicated by the character 5 a body having angularly disposed cutting surfaces each one of which is designated by the character 6 on the appended drawing. The cutting surfaces are angularly disposed and terminate upwardly in a cutting edge 7. The cutting edges 7 are all the exact same height above the backface 8 of the drill bit. The said cutting edges are either at right angle to each other or parallel to each other when viewed from the top. An inspection of FIGURE 1 of the drawings makes it clear that the cutting edges 7 form four expanded capital letter Ts. It is noted that each cutting edge is positioned at right angles to each of the two adjacent cutting edges and parallel to the diametrically opposed cutting edge. The wing angle of one of the foresaid pairs of cutting surfaces is designated by the reference character 9 in FIGURES 2 and 3 of the appended drawing. The gauge of this novel rock drill bit is noted by the character 10 in the appended drawings while the gauge area is noted by the numeral 11 in FIGURE 3. An opening 12 for cleansing air or liquid is shown in the center of the body of this rock drill bit whose lowermost portion 13 may terminate in any desired form. The length 14 of the bit may be sufiicient to permit it to be cutoff at the said backface which can then be provided with an internally threaded opening adapted to receive the mating portion of a rotary precision drill (not shown in the appended drawing) that is so well known to those experienced in 3,149,686 Patented Sept. 22, 1964 the arts as to need no further explanation, or, the bit may lcnle provided with a shank as means of securement to a rill.

The operation of this invention is obvious to users of rock drill bits so little need be said on the subject in this specification other than the fact that as previously noted, the cutting edges all travel in a more nearly longitudinal direction than the cutting edges of other drill bits. Although the structure for driving the bit is conventional and is not claimed, a brief description of the operation will serve as background. As is customary, the bit is rotated in a counter-clockwise direction. Periodically the bit receives an impact. The bit travels in a counterclockwise direction as it is both rotated and bounced in a slightly upward direction after each blow of the drilling machine. It is the return of the bit to the rock in a twirling movement which causes excessive wear of a bit. It is the traveling of the cutting edges of the bit in a more nearly longitudinal direction that prevents extensive wear of this unique rock drill bit, a feature of my design that it will be remembered is one of the objects of my invention, the construction and operation of which I have now fully described.

From the foregoing it will now be seen that there is herein provided an improved rock drill bit which accomplishes all of the objects of my invention, and others, including many advantages of great practical utility and commercial importance.

An many embodiments may be made of this inventive concept, and as many modifications may be made in the embodiment hereinbefore shown and described, it will be understood that all matter herein is to be interpreted merely as illustrative, and not in a limiting sense.

What I, therefore, claim as new and desire to protect by Letters Patent is:

1. A rock drill bit of the character described, comprising a body having a plurality of cutting edges that form four expanded capital letter Ts, the said edges all being the same height above the backface of the said rock drill bit which is provided with a shank to be received and secured in one end of a rotary drill.

2. A rock drill bit of the character described, comprising a body having a plurality of cutting edges that form four expanded capital letter Ts, the said edges all being the same height above the backface of the said rock drill bit which is provided with a shank to be received and secured in one end of a rotary drill and an opening in the approximate center thereof for the expulsion of some form of a liquid to wash away the rock being cut.

3. A rock drill bit of the character described, comprising a body having four angularly disposed cutting surfaces which form four expanded capital letter T's when viewed from the top, each cutting edge is positioned at right angles to each of the two adjacent cutting edges and parallel to the diametrically opposed cutting edge, the said edges being the same height above the backface of the said rock drill bit which is provided with a shank to be received and secured in one end of a rock drilling machine.

References Cited in the file of this patent UNITED STATES PATENTS 48,892 Bates July 25, 1865 158,704 Hanrahan Ian. 12, 1875 903,936 Wilson et al Nov. 17, 1908 1,989,119 Thompson Jan. 29, 1935 2,179,689 Earnheart Nov. 14, 1939 2,507,222 Phipps May 9, 1950 3,005,504 Mayhew Oct. 24, 1961 

1. A ROCK DRILL BIT OF THE CHARACTER DESCRIBED, COMPRISING A BODY HAVING A PLURALITY OF CUTTING EDGES THAT FORM FOUR EXPANDED CAPITAL LETTER T''S, THE SAID EDGES ALL BEING THE SAME HEIGHT ABOVE THE BACKFACE OF THE SAID ROCK DRILL BIT WHICH IS PROVIDED WITH A SHANK TO BE RECEIVED AND SECURED IN ONE END OF A ROTARY DRILL. 